Recently, there is growing demand for wireless streaming delivery of multimedia data such as video and audio from a transmission device to a plurality of reception devices (for example, mobile terminals). For example, a transmission device compresses content at a plurality of transmission rates in advance and transmits the content by IP multicasting, while a reception device receives the content while selectively switching between appropriate transmission rates according to the congestion conditions of the network between the reception device and the transmission device.
The method corresponding to IP multicasting may be a streaming method using the Real-time Transport Protocol (RTP) stipulated in IETF RFC 3550 using the User Datagram Protocol (UDP) as the transport protocol, otherwise known as RTP streaming. RTP streaming is also capable of transmitting to a reception device via a wireless local area network (LAN) conforming to the IEEE 802.11 standard, and is effective in the case of transmitting to a plurality of reception devices by multicasting.
Particularly, when considering transmission to a plurality of reception devices, in the case of a wired connection, the link between a relay and a reception device may be connected independently. However, in the case of wireless transmission, the wireless transmission frequency band is shared among all reception devices, and the use of multicasting is effective because unicast transmission to a plurality of reception devices cannot be conducted efficiently.